The present invention relates to a windshield defrosting air duct for a work vehicle and in particular to an air duct formed by a single piece air distribution member positioned adjacent to the windshield that uses the windshield surface to define one side of the air duct.
Work vehicles, such as an agricultural tractor, etc. typically provide operator cabs having a large front windshield to maximize visibility for the vehicle operator. To remove condensation from the interior surface of the windshield, a defroster system is provided that discharges air over the surface of the glass. The defroster system typically includes a plurality of air ducts formed in the housing covering the steering wheel support structure. The air ducts lead to discharge outlets that direct the air toward the glass surface. Typically these air ducts are formed of multiple molded plastic components joined together to form enclosed air ducts leading to the air outlets. The structure of these air ducts often requires a multiple piece construction or single piece molding techniques, such as rotational molding, that have large dimensional tolerances.
The present invention overcomes the difficulties of prior air duct assemblies by utilizing a single piece injection molded distribution member carried by the steering wheel support structure. The air distribution member forms three sides of an air duct with the fourth side of the air duct left open. The opened side is positioned adjacent to the vehicle windshield where the windshield forms the fourth side of the air duct. Since the distribution member itself does not form an enclosed air duct, a single piece injection molded component can be used as the air distribution member forming three sides of the duct.
The distribution member is placed in contact with the glass or it can be slightly spaced from the glass. If spaced from the glass, a continuous layer of air flows from the air distribution member over the surface of the glass The airflow is not restricted to flow solely from the air outlets. This ensures complete coverage of a glass surface, especially the glass surface closest to the steering wheel support structure, between the air outlets.
The air distribution member is formed with a plurality of vanes in the air duct that divide the duct into multiple air channels each terminating in an air outlet. The vanes include a center vane that begins near an air inlet into the air duct that divides the duct into two separate flow paths to insure that the air is evenly distributed laterally.